Vulcanized rubber compositions used in tires, belts, hoses and similar products are required to have good flex fatigue resistance and good oxidative stability, even in oxygen rich environments. Oxygen rich environments often lead to degradation processes induced by ozone and oxygen attack. In particular, certain tire components such as sidewalls, and the like, stay almost in untouched form through their life because their surfaces do not come in contact with objects such as road surfaces which tend to abrade rubber surfaces. Thus, these components are subject to degradation through oxidation and ozonation. These components have typically been made using formulations containing antidegradants that inhibit or prevent the degradation processes of oxygen and ozone attack.
A number of tire compositions have been formulated utilizing polymers of fluorinated ethylenes. In Japanese Patent 86 284 390, a composition is described which contains polyfluorinated ethylenes or polymers containing fluorinated olefin monomers to enhance the lubricating properties of the rim cushions so that tires can be mounted more easily without causing wear to the rim cushion and to reduce any detachment or tearing.
In a series of U.S. Pat. Nos. including 4,215,178, 4,075,158 and 4,965,152 compositions comprising given weights of polytetrafluoroethylene (PTFE) and molybdenum sulfide are disclosed for use in tire applications. These compositions require the presence of PTFE and molybdenum disulfide to achieve the advantages found in those compositions.
In U.S. Pat. No. 3,600,309, a composition is described for reducing die-plating and drag during rubber extrusion. This composition contains finely divided PTFE for use in a wide variety of elastomers to facilitate extrusion.
None of the above patents indicate that PTFE in a compatabilized format could aid in sidewall durability as it relates to ozone stability flex fatigue resistance.